MC34142

The MC34142 has the following features including SMARTMOS Technology;35 V Maximum Output Off-State Voltage;500 mA Maximum Output Sink Current;Regulated Output Saturation Voltage;16 Open Drain MOS Outputs;4 Input CMOS Decoder;Chip Select and Output Enable Input Pins;Internal Freewheel Diodes;Functional Equivalent to the UCN5816A.

The MC34142 is a high pertormance 4 to 16 multiplexed driver. This integrated circuit features a 4 to 16 decoder, 16 open drain N-channel MOS output devices with clamp diodes. The outputs are controlled by 4 address inputs, an output enable, and a chip enable.Typical applications include solenoid drivers, LED drivers, lamp drivers,and relay drivers.This device is offered in a PLCC and a wide body surtace mount package.The MC34142 is a high performance 4 x 16 multiplexed driver. This integrated circuit features a 4 x 16 decoder, 16 open-drain output devices with clamp diodes, an output enable, and a chip enable. Typical applications include solenoid drivers, LED drivers, lamp drivers, and relay drivers.The inputs to this device are TTLICMOS compatible,making them ideal to be driven from a microcomputer. Table  1  is a truth table for the input logic versus the appropriate activated output. Notice, for a specific input,only one output can be activated.

The outputs on the MC34142 are open drain DMOS power MOSFETs. Each output is capable of sinking in excess of 500 mA. The outputs have been uniquely designed to control the "on-resistance" of the power MOSFET. The voltage drop across  the  MC34142  is  regulated  and temperature compensated to give a consistent saturation voltage characteristic over load and temperature. Figure 2 shows a curve of the Output Saturation Voltage versus Sink Current.Each output also has a flyback diode clamp to protect the device from inductive load kickbacks. Special care should be taken when laying out the printed circuit board to use these clamp diodes effectively. A capacitor of MC34142 should be placed close to the K1 and K2 clamp outputs.